ISO 18279 Brazed joints usually contain imperfections of various types, some of which will be detrimental in almost every case but others may be detrimental or harmless, depending entirely on the service requirements of the joint in question. Therefore it will frequently be necessary to classify the imperfections in a brazed joint and then try to assess the significance of their effects on the behaviour of the joint in service. The classification is, relatively, easy describes the imperfections that most commonly occur. The assessment of significance is not easy.
For welded joints, there has been extensive work carried out for many years on the significance of imperfections in service but such work has not been carried out on brazed joints. Moreover the work on welded joints is only rarely relevant to brazed joints, mainly because of differences in geometry and stressing. Therefore this standard cannot give definitive quality levels for brazed joints. These can only be produced as experience is gained from industrial applications. However, Annex B gives some suggestions for quality levels for general applications, which may be of help where detailed information is not available. It has to be emphasized that the use of quality levels can only be successful if the imperfections that are relevant to the application of the brazed joint are determined.
